By the year 2069, humanity had depleted the Earth’s great forests into small plots of police protected tree sanctuaries. Due to years of escalating carbon emissions and deforestation, the planet’s atmosphere became over-saturated with carbon dioxide. The sparse forests were too small to recycle the air into oxygen needed by Earth’s fauna. The logging industry became humanity’s unlikely saviors when they teamed with NASA scientists. They discovered by genetically modifying certain giant redwood trees for space flight, the entire solar system itself could be a new kind of forest. Unlike a forest rooted to the Earth, Solar Powered Space Trees (S.P.S.T.) migrate throughout space propelled by the solar winds and planetary gravitational slingshots. On their elliptical journey from Venus to Neptune, they use their inherent solar powers to create massive volumes of oxygen from the carbon dioxide stored within their protective sphere. By the time they reach the moon of Triton, their oxygen stores are full and their carbon dioxide supply has dwindled.

While orbiting Neptune, small robotic spacecraft rendezvous with the solar traveler and replace its oxygen tanks with a new supply of carbon dioxide mined from Mars’ atmosphere. These “Solar Harnessing Interplanetary Traveling” robots (S.H.I.T. robots) then reset the tree’s trajectory back towards Earth where they will do another flyby of Venus only to return again to Neptune years later. The precious oxygen canisters hitch a ride on the returning S.P.S.T.s where they are eventually jettison down to Earth on the flyby approach, and get replaced by fresh carbon dioxide canisters mined from Earth’s atmosphere.

This cyclical journey continued for thousands of years allowing inhabitants of Earth to live not only on their own planet, but also on the Moon, Mars, and other small moons within the solar system as well. This gave humanity more room to populate, so the forests of Earth became naturally replenished. Soon the S.P.S.T.s were no longer necessary, as Earth’s oxygen levels were once again in balance from its native flora. After the robots became sentient, they understood the importance of their symbiosis with their organic brethren. The robot’s and the tree’s selfless gift of oxygen to humanity was not forgotten as they were left to freely roam in harmony, to multiply and evolve, with no more earthly obligations in the boundless forests of outer space.